High-temperature thermoset polyimides containing disubstituted acetylene end groups

Novel phenylethynyl-terminated PMDA-type polyimides based on KAPTON backbone structures derived from 2-phenyl-4,4′-diaminodiphenyl ether

“…An increase in E 0 was also observed at temperatures close to 420 1C because of thermo-oxidative crosslinking that occurred during measurements in air. The e b of the cured resin was found to be exceedingly high (414%), indicating that the thermal reaction mechanism of the PEPA was mainly chain extension without further cyclization or crosslinking, as also reported by McGrath et al [8][9][10] Novel phenylethynyl-terminated PMDA-type PIs M Miyauchi et al…”

“…[5][6][7] The cured PI exhibits a moderate T g of 270 1C and more than 30% elongation-at-break (e b ) for a film at room temperature. Because the formation of the converted cured resin was mainly a result of chain extension of the imide oligomers, arising from the thermo-additional polymerization of PEPA, [8][9][10] the cured PETI-5 shows very similar properties to that of a thermoplastic and not a thermoset. Furthermore, it was noted that the phenylethynyl end cap offers distinct advantages such as a large processing window and good thermo-oxidative stability when cured compared with other reactive end caps such as nadic acid derivatives and maleic acid.…”

Phenylethynyl-terminated polyimide, exfoliated graphite nanoplatelets, and the composites: an overview

“…Their thermal characteristics, including high temperature stability and cure behavior, are critical to successful processing and to the final properties of the resulting polyimide. For aerospace and aircraft applications, advanced polymer materials must successfully maintain their properties at high service temperatures over a long exposure time [3][4][5].…”

“…Many investigators have utilized a variety of analytical methods to examine the imidization and/or cure of ethynylor phenylethynyl-terminated imide polymers, including, for example, FTIR [19,24,35], DSC [19,23,36], thermogravimetric analysis (TGA) [23], high performance liquid chromatography (HPLC) [4], and solid-state 13 C nuclear magnetic resonance (NMR) [37] methods. Nonetheless, each of the approaches has limitations.…”

“…Their thermal characteristics, including high temperature stability and cure behavior, are critical to successful processing and to the final properties of the resulting polyimide. For aerospace and aircraft applications, advanced polymer materials must successfully maintain their properties at high service temperatures over a long exposure time [3][4][5].The important parameters influencing the heat resistance of a polymeric material are its glass transition temperature (T g ), melting point (T m ), thermal stability, and etc., which may depend on its thermal history. Accordingly, polymers that are used to fulfill such high temperature performance should exhibit a high T g or T m and have excellent thermal stability.…”